ELSEVIER Microporous and Mesoporous Materials 21 ( 1998) 183-197 New structures -new insights: Progress in structure analysis of nanoporous materials Hermann Gies ‘,*, Bernd Marler ‘, Silke Vortmann a, Uwe Oberhagemann a, Parwis Bayat a, Kirsten Krink a, Jordi Rius b, Ingo Wolf a, Colin Fyfe ’ a Inst. fiir Mineralogie, Ruhr-Universitdt Bochum, 44780 Bochum, Germany b Institut de Ci2ncia de Materials de Barcelona, CSIC, Bellaterra, Catalunya, Spain ’ Depr. qf Chemisfry, UBC Vancouver, Vancouver, Canada Received 13 September 1997;received in revised form 10 November 1997;accepted 17 December 1997 Abstract In the recent past structure determination of microporous materials has experienced considerable developments in methodology. The FOCUS method: high resolution powder diffraction data used for direct method structure solution, in combination with crystal chemistry basedmodelling. The models are retrieved from electron densit)r maps calculated in direct method runs, energy minimized and checked through for realistic angles and distances values. The SUM-TF method: diffraction patterns at moderate resolution analysed with direct methods using a modified tangent formula which includes Patterson information for the structure solving. In this way the atomic resoiution criterion for direct methods is bypassed. This overview gives a summary of the structures successfully solved using these new techniques. 0 1998 Elsevier Science B.V. All rights reserved. Keywords: Powder diffraction; Structure solution; Rietveld analysis; Zeolites; Layer silicates; VNI; RUB-15; RUB-18; Kanemite 1. Introduction Nanoporous materials can be either crystalline or amorphous solids which are widely used as ion exchangers, heterogeneouscatalysts, supports, and sorbents [I]. Their chemical and physical proper- ties are closely related to the specific crystal struc- ture of the material, rendering structure characterization an indispensable task [2]. * Corresponding author. Fax: +49 234 7094433; e-mail: hermann.gies@ruhr-uni-bochum.de Researchers working in the fields of synthesis, modification, and application of nanoporous mate- rials extensively use detailed structural knowledge in order to achieve meaningful progress in their respective fields. Many different techniques are used to describe the structural properties of a material; however, all information gained is restricted to the particular probe/material inter- action. Whereas diffraction studies probe the long range periodicity of crystalline materials, spectro- scopic techniques are most sensitive to changes in the local atomic environments in crystalline and amorphous materials. Sorption and diffusion 1387..181 l/98/%19.00 0 1998Elsevier ScienceB.V. All rights reserved. PII: St387-1811(98)00003-l